基于制导一体化设计实现大入射角攻击目标的技术研究

考虑到导弹弹体和控制回路的特性,结合比例导引规律,得到了一种便于工程实施的综合制导律.该制导律改善了制导性能,通过平衡舵偏补偿技术,实现了高精度、大入射角攻击目标的功能.数学仿真结果显示了该方法的有效性.     

无线电定位技术在蜂窝通信系统中的应用及实现

当前,移动用户对基于无线定位技术的新业务的需求不断增加,推动了对无线测距及定位技术的深入研究,向用户提供精确的定位信息已经成为新一代PCS系统的标准业务之一。主要介绍几种基于现有蜂窝通信系统的无线定位技术的实现原理,所要解决的主要问题和应用前景。     

被动传感器系统分层快速关联算法

被动传感器系统的核心问题是测量数据关联问题.在被动传感器系统中,多维分配算法是一种有效的关联算法,但多维分配本身是一个NP-hard问题并且建立候选分配树需耗费大量时间.为解决被动传感器系统中测量数据快速关联问题,本文提出了分层快速关联算法.该算法通过统计量检验减少候选关联,分层搜索寻找正确关联.仿真实验结果表明,分层快速关联算法是一种有效的关联算法,正确关联率高于拉格朗日松驰算法.     

Differential geometric modeling of guidance problem for interceptors

It is a comparatively convenient technique to investigate the motion of a particle with the help of the differential geometry the-ory,rather than directly decomposing the motion in the Cartesian coordinates.The new model of three-dimensional (3D) guidance problem for interceptors is presented in this paper,based on the classical differential geometry curve theory.Firstly,the kinematical equations of the line of sight (LOS) are gained by carefully investigating the rotation principle of LOS,the kinematic equ...     

陕西彬长矿区NDVI3g(1982-2013)变化趋势及气候响应

过去30 a,全球归一化差值植被指数(NDVI)呈增加趋势,植被返青期(SOS)提前,枯黄期(EOS)滞后,生长期(LOS)延长。作为人类经济活动最密集的工矿区,其生态环境问题是环境与发展的焦点问题之一,在全球变化的背景下,研究矿区及周边地区NDVI趋势,能很好地反映区域尺度上非自然生态区植被变化及对全球变化的响应。基于GIMMS AVHRR NDVI3g长时间序列遥感影像,利用IDL编程、线性回归、趋势拟合提取研究区1982—2013年植被覆盖的物候信息,分析矿区、缓冲区(10 km,20 km)及生态校验区月度、季度、年际变化情况,推算出植被SOS,EOS与LOS长度变化趋势,并结合气象观测记录分析气候驱动因子(降水、气温)与NDVI变化相关性。时序相关性分析表明:32 a彬长矿区年均NDVI总量随时间序列缓慢升高,32 a增长百分比达13. 31%;生态校验区NDVI总量随时间序列升高趋势明显,32 a增长百分比达19. 45%;受人类活动影响,矿区NDVI阶段增长百分比明显低于生态校验区。空间相关性分析表明:彬长矿区NDVI原始基底值高于校验区,植被SOS提前6±3 d,EOS滞后5±3 d,LOS延长11±3 d;生态校验区植被SOS提前3±3d,EOS滞后3±3 d,LOS延长6±3 d;矿区植被LOS延长天数高于生态校验区5 d。气候相关性分析表明:彬长矿区处于半湿润气候区,植被对气温变化的响应高于降水,植被生长对降水有2～3 a的滞后性,NDVI的增加与该区气温升高、降水减少的共同作用有关。研究认为,采矿活动使得矿区及其周边地区植被活动放缓,年均NDVI增长率明显低于生态校验区;在全球变化作用下,植被LOS延长的基础上,人类活动使得矿区植被LOS被再度延长。     

一种视距与非视距混合环境下RSS定位方法

针对当前视距与非视距混合环境下无线定位精度不高且结果不太稳定问题,提出一种基于接收信号强度的动态定位方法. 该方法采用混合高斯模型来同时刻画视距与非视距传播的影响,克服了现有方法中视距与非视距传播识别的难题,并利用动态期望最大算法来实时调整模型参数,以适应环境的时变特性. 进一步,考虑到实际定位中测试位置几何关系对定位精度的影响,提出了基于最佳几何精度衰减因子组合的测试点选取方法. 仿真实验表明,在视距与非视距混合环境下该方法不仅具有较高的定位精度,而且能够适应环境的动态变化.     

捷联成像制导系统的若干问题探讨

对比捷联成像导引头和传统成像导引头的特点，指出捷联成像寻的制导技术应用到实际的导弹系统中，需要解决视线角速率提取、数学平台的实现以及制导和控制系统综合设计等问题。给出了各坐标系之间的转换关系，据此推导了捷联成像寻的制导的弹体姿态解耦算法。针对捷联成像导引头的大测量噪声以及系统的非线性，介绍了采用Unscented卡尔曼滤波器估计视线角速率的基本原理，并对捷联成像制导与控制系统进行了分析，给出了制导与控制系统综合设计的思路。     

An Investigation of MIMO Performance in the Indoor Ricean Environment

In this paper, we investigate the Multiple-Input Multiple-Output (MIMO) channel capacity in indoor Ricean channels based on MIMO channel measurements at 2.45 GHz. The measured data is analysed using a super resolution parameter estimation algorithm. Our results demonstrate that the line-of-sight (LOS) component in a Ricean scenario influences indoor MIMO performance through increased spatial correlation between array elements. We found that indoor channels with higher values of Ricean K factor have smaller numbers of effective multipath components and increased spatial correlation. Measurement results also showed that, the effect of varying antenna height on indoor MIMO capacity is also due to the spatial correlation of multipath propagation and has a close relationship with the separation between the transmitter and receiver. Zhongwei Tang is currently with the Wireless Technologies Laboratory at CSIRO. He was with Microwave and Wireless Technology Research Laboratory (MWTRL), Information and Communication Group, Faculty of Engineering of the University of Technology Sydney, Australia, where he pursued his Ph.D. Degree. His current research interests include RF propagation, MIMO Space-Time channel measurements, characterization and channel modelling, smart antennas, MIMO systems and array signal processing. Ananda S. Mohan is currently a member of the Faculty of Engineering, University of Technology, Sydney (UTS), Australia where he leads research on antennas, microwaves, wave propagation, and wireless technology. He received a Ph.D. degree in electrical communication engineering from the Indian Institute of Technology, Kharagpur, India and was a Scientist and Senior Scientist at the Research and Training Unit for Navigational Electronics, Hyderabad, India. At UTS, he directed the Sydney microwave design resource centre and was the associate program leader of the co-operative research centre for satellite systems. He currently directs the microwave and wireless technology research laboratory and a core member of the university research centre on health technologies. His current teaching and research interests include wireless mobile communications, microwaves and antennas, smart antennas and applications of microwave and wireless technology in medicine and has obtained many competitive research grants in these areas. Dr. Mohan was a co-recipient of the Priestly memorial award from the Institute of Radio and Electronic Engineers (IREE), Australia. He was a member of the organizing and technical Program Committees of the IEEE Globecom'98, APMC 2000, and International Symposium on Wireless Systems and Networks, 2003 and IASTED International Conference on Antennas, Radar, and Wave Propagation, for 2004 and 2005.     

陀螺稳定平台伺服系统非线性特性补偿控制

在详细分析导引头陀螺伺服稳定平台系统模型和运行特性的基础上,提出采用带非线性加速度负反馈并联校正环节的变速积分PID控制算法.功能样机试验运行效果表明,该系统具有快速的动态响应和较强的抗非线性干扰能力,满足了设计指标要求.     

车载设备视轴稳定与跟踪系统设计

本文进行了车载设备视轴稳定与跟踪系统的设计与分析。首先从理论上分析了两轴稳定系统隔离载体角运动的原理，奠定本系统工作的理论基础。然后根据系统性能指标要求．设计了前馈-反馈复合控制和位置．速度双环控制相结合的控制系统，仿真与初步试验均表明设计是正确的。